Re: [PATCH V2 6/8] spi: spi-geni-qcom: Add interconnect support

[Matthias Kaehlcke <mka@chromium.org>]

Hi Akash,

On Fri, Mar 13, 2020 at 06:42:12PM +0530, Akash Asthana wrote:
> Get the interconnect paths for SPI based Serial Engine device
> and vote according to the current bus speed of the driver.
> 
> Signed-off-by: Akash Asthana <akashast@codeaurora.org>
> ---
>  - As per Bjorn's comment, removed se == NULL check from geni_spi_icc_get
>  - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure
>  - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting
>    path handle
>  - As per Matthias comment, added error handling for icc_set_bw call
> 
>  drivers/spi/spi-geni-qcom.c | 74 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 73 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index c397242..09c4709 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -118,6 +118,19 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
>  	return ret;
>  }
>  
> +static int geni_spi_icc_get(struct geni_se *se)
> +{
> +	se->icc_path_geni_to_core = devm_of_icc_get(se->dev, "qup-core");
> +	if (IS_ERR(se->icc_path_geni_to_core))
> +		return PTR_ERR(se->icc_path_geni_to_core);
> +
> +	se->icc_path_cpu_to_geni = devm_of_icc_get(se->dev, "qup-config");
> +	if (IS_ERR(se->icc_path_cpu_to_geni))
> +		return PTR_ERR(se->icc_path_cpu_to_geni);
> +
> +	return 0;
> +}

As per my comments on (https://patchwork.kernel.org/patch/11436895/#23222713),
the above function could be replaced by calling a 'geni_icc_get()' (or so, to
be created) provided by the geni SE driver.

> +
>  static void handle_fifo_timeout(struct spi_master *spi,
>  				struct spi_message *msg)
>  {
> @@ -234,6 +247,20 @@ static int setup_fifo_params(struct spi_device *spi_slv,
>  		return ret;
>  	}
>  
> +	/*
> +	 * Set BW quota for CPU as driver supports FIFO mode only.
> +	 * Assume peak bw as twice of avg bw.
> +	 */
> +	se->avg_bw_cpu = Bps_to_icc(mas->cur_speed_hz);
> +	se->peak_bw_cpu = Bps_to_icc(2 * mas->cur_speed_hz);
> +	ret = icc_set_bw(se->icc_path_cpu_to_geni, se->avg_bw_cpu,
> +			se->peak_bw_cpu);
> +	if (ret) {
> +		dev_err(mas->dev, "%s: ICC BW voting failed for cpu\n",
> +			__func__);
> +		return ret;
> +	}
> +
>  	clk_sel = idx & CLK_SEL_MSK;
>  	m_clk_cfg = (div << CLK_DIV_SHFT) | SER_CLK_EN;
>  	spi_setup_word_len(mas, spi_slv->mode, spi_slv->bits_per_word);
> @@ -578,6 +605,15 @@ static int spi_geni_probe(struct platform_device *pdev)
>  	spin_lock_init(&mas->lock);
>  	pm_runtime_enable(dev);
>  
> +	ret = geni_spi_icc_get(&mas->se);
> +	if (ret)
> +		goto spi_geni_probe_runtime_disable;
> +	/* Set the bus quota to a reasonable value for register access */
> +	mas->se.avg_bw_core = Bps_to_icc(CORE_2X_50_MHZ);
> +	mas->se.peak_bw_core = Bps_to_icc(CORE_2X_100_MHZ);
> +	mas->se.avg_bw_cpu = Bps_to_icc(1000);
> +	mas->se.peak_bw_cpu = Bps_to_icc(1000);
> +
>  	ret = spi_geni_init(mas);
>  	if (ret)
>  		goto spi_geni_probe_runtime_disable;
> @@ -616,14 +652,50 @@ static int __maybe_unused spi_geni_runtime_suspend(struct device *dev)
>  {
>  	struct spi_master *spi = dev_get_drvdata(dev);
>  	struct spi_geni_master *mas = spi_master_get_devdata(spi);
> +	int ret;
> +
> +	ret = geni_se_resources_off(&mas->se);
> +	if (ret)
> +		return ret;
>  
> -	return geni_se_resources_off(&mas->se);
> +	ret = icc_set_bw(mas->se.icc_path_geni_to_core, 0, 0);
> +	if (ret) {
> +		dev_err_ratelimited(mas->dev, "%s: ICC BW remove failed for core\n",
> +			__func__);
> +		return ret;
> +	}
> +
> +	ret = icc_set_bw(mas->se.icc_path_cpu_to_geni, 0, 0);
> +	if (ret) {
> +		dev_err_ratelimited(mas->dev, "%s: ICC BW remove failed for cpu\n",
> +			__func__);
> +		return ret;
> +	}

the ICC stuff above would become:

	ret = geni_icc_vote_off(&mas->se);
	if (ret)
		return ret;

with the consolidated code in geni SE.

> +
> +	return 0;
>  }
>  
>  static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
>  {
>  	struct spi_master *spi = dev_get_drvdata(dev);
>  	struct spi_geni_master *mas = spi_master_get_devdata(spi);
> +	int ret;
> +
> +	ret = icc_set_bw(mas->se.icc_path_geni_to_core, mas->se.avg_bw_core,
> +		mas->se.peak_bw_core);
> +	if (ret) {
> +		dev_err_ratelimited(mas->dev, "%s: ICC BW voting failed for core\n",
> +			__func__);
> +		return ret;
> +	}
> +
> +	ret = icc_set_bw(mas->se.icc_path_cpu_to_geni, mas->se.avg_bw_cpu,
> +		mas->se.peak_bw_cpu);
> +	if (ret) {
> +		dev_err_ratelimited(mas->dev, "%s: ICC BW voting failed for cpu\n",
> +			__func__);
> +		return ret;
> +	}

and this:

	ret = geni_icc_vote_on(&mas->se);
	if (ret)
		return ret;

>  	return geni_se_resources_on(&mas->se);

possibly you could even do the ICC voting from geni_se_resources_on/off()
it seems the two are always done together for UART, I2C and SPI.